[flexi-streams-devel] Re: New release 0.13.0

[Edi Weitz]

On Fri, 09 Nov 2007 03:27:50 +0300, Anton Vodonosov <vodonosov at mail.ru> wrote:

> Sorry about tabs. You may consider setting emacs variable
> indent-tabs-mode to nil in your sources.

I have that, but the tabs were in your patch.  Emacs won't
automatically remove tabs introduced from patches, you'd have to do
that automatically...

> Few days ago I've tried to measure performance improvement gained by
> buffering in stream-write-sequence. It turned out that in real word
> scenarios no improvement at all, because underlying stream always
> provides necessary buffering.
>
> For example, to notice changes in performance when working with
> file, we must use unbuffered file stream, which is of course very
> uncommon (moreover, in case of normal, buffered, file stream
> performance is slightly worse because we do some additional work on
> our side; but you must do lot of output to notice this).
>
> Therefore, I've decided to test it with network stream. I've setup
> hunchentoot and configured simple easy-handler that just return a
> 10k string. Also, I've changed the make-socket-stream function to
> create unbuffered socket (:buffering :none in sbcl).
>
> On the other host the was drakma performing a hundred of requests to
> this handler.
>
> I've tested this setup with two versions of flexi streams: 0.11.0 -
> without buffering and 0.13.1 - with buffering. It is surprising (for
> me) that in this case there was no performance difference too.
>
> Using sniffer (ethreal) I've discovered that even in case if we do
> not do any buffering on sbcl side, buffering is anyway performed -
> by TCP implementation. When we do lot of write-byte it sends first
> packet with data length = 1, but all subsequent packets are of size
> > 1k.  Looks like they have some micro timeout after our write-byte
> to see whether we will do write-byte again.
>
> Maybe this buffering in stream-write-sequence is unnecessary...

Hmmm....

ISTR that I did some simple tests with your patch and that there was a
noticeable difference, but I don't have the results anymore.  Anyway,
I think I'll leave it like it is for now.

> P.S. There is a little test for stream-line-column function in the
> attach.

Thanks.

Cheers,
Edi.